Working virtually with business owners and individuals locally and world-wide. Your "get it done" Administration Consultant with over 20 years experience - Researcher, Genealogist, Writer, Editor, Bookkeeper, PA and Travel Co-ordinator. Primarily specialising in family history, genealogy, historical research, aviation and travel issues. I also enjoy the variety of covering other topics as required. Click here to contact me

Also check if the messed-up message displays a long display name for the e-mail address.
If there was a settings change on the sender's side, the e-mail address may now be an unverified address in your e-mail programme.

Another option: Select the entire document (Ctrl + A) and hit Ctrl + Q. This will remove any formatting in it.

UPDATE: 06 July 2012 - Subscribers of Yahoo Groups are reporting this vertical text problem. Yahoo Groups recently changed their settings / format. If you receive your group messages in the Digest format and see vertical text, here is a solution:

Sign in to your Group with your Yahoo! ID
Under Edit Membership go to Step 3. Message Preference
Make sure you select Traditional